Multicopter with boom-mounted rotors

ABSTRACT

A multicopter with boom mounted rotors is disclosed. In various embodiments, a multicopter includes multiple rotors, each mounted substantially horizontally on a distal end of a boom. The multicopter further includes a plurality of boom extensions, each boom extension being associated with a corresponding boom and each boom extension being configured to extend an associated distal end of said corresponding boom by an amount determined based at least in part on a swept area associated with a rotor mounted at or near said associated distal end. The multicopter includes a material, such as netting, secured to the aircraft and of a size sufficient to reach a far end of one or more of said boom extensions.

CROSS REFERENCE TO OTHER APPLICATIONS

This application is a continuation of co-pending U.S. patent applicationSer. No. 15/249,074 entitled MULTICOPTER WITH BOOM-MOUNTED ROTORS filedAug. 26, 2016 which is incorporated herein by reference for allpurposes.

BACKGROUND OF THE INVENTION

Small scale, lightweight, and personal aircraft have been described. Forexample, some have imagined small aircraft used routinely for personaltransportation, such as to get to and from work or school, and/or forentertainment.

Unlike unmanned aircraft, such as drones, occupant safety is asignificant concern in the case of a manned aircraft. In addition, theability to store and/or transport a personal aircraft may become adesign consideration. For example, a personal aircraft may need to betransported by ground, e.g., in a trailer or on a truck bed, to be takento a location from which the aircraft can safely take off and land.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the invention are disclosed in the followingdetailed description and the accompanying drawings.

FIG. 1 is a diagram illustrating an embodiment of a multicopter withflotation landing gear.

FIG. 2 is a block diagram illustrating an embodiment of booms and rotorsof a multicopter with flotation landing gear.

FIG. 3 is a diagram illustrating an embodiment of booms and rotors of amulticopter with flotation landing gear.

FIG. 4 is a block diagram illustrating an embodiment of booms, rotors,and protective material of a multicopter with flotation landing gear.

FIG. 5 is a diagram illustrating a top view of an embodiment of amulticopter with flotation landing gear.

FIG. 6 is a diagram illustrating a side view of an embodiment of amulticopter with flotation landing gear.

FIG. 7 is a diagram illustrating a side view of an embodiment of amulticopter with flotation landing gear.

FIG. 8 is a diagram illustrating a front view of an embodiment of amulticopter with flotation landing gear.

DETAILED DESCRIPTION

The invention can be implemented in numerous ways, including as aprocess; an apparatus; a system; a composition of matter; a computerprogram product embodied on a computer readable storage medium; and/or aprocessor, such as a processor configured to execute instructions storedon and/or provided by a memory coupled to the processor. In thisspecification, these implementations, or any other form that theinvention may take, may be referred to as techniques. In general, theorder of the steps of disclosed processes may be altered within thescope of the invention. Unless stated otherwise, a component such as aprocessor or a memory described as being configured to perform a taskmay be implemented as a general component that is temporarily configuredto perform the task at a given time or a specific component that ismanufactured to perform the task. As used herein, the term ‘processor’refers to one or more devices, circuits, and/or processing coresconfigured to process data, such as computer program instructions.

A detailed description of one or more embodiments of the invention isprovided below along with accompanying figures that illustrate theprinciples of the invention. The invention is described in connectionwith such embodiments, but the invention is not limited to anyembodiment. The scope of the invention is limited only by the claims andthe invention encompasses numerous alternatives, modifications andequivalents. Numerous specific details are set forth in the followingdescription in order to provide a thorough understanding of theinvention. These details are provided for the purpose of example and theinvention may be practiced according to the claims without some or allof these specific details. For the purpose of clarity, technicalmaterial that is known in the technical fields related to the inventionhas not been described in detail so that the invention is notunnecessarily obscured.

A multicopter aircraft is disclosed. In various embodiments, themulticopter aircraft comprises multiple rotors, each mountedsubstantially horizontally on or near a distal end of a boom, i.e., anend of the boom that extends away from a central point, axis, fuselage,and/or other structure of the aircraft. The multicopter aircraftcomprises a plurality of boom extensions, each boom extension beingassociated with a corresponding boom and each boom extension beingconfigured to extend an associated end of said corresponding boom by anamount determined based at least in part on a swept area associated witha rotor mounted at or near said associated end. The aircraftadditionally comprises a net or other non-rigid protective material(e.g., sailcloth, tarp) secured to said aircraft and having an outerfree (unsecured) portion of a size sufficient to reach a far end of oneor more of said boom extensions.

In various embodiments, the net or other material extended over saidboom extensions provides a barrier between an occupant/user of themulticopter aircraft and said rotors, decreasing the likelihood that theoccupant/user will come in contact with said rotors.

In some embodiments, the multicopter aircraft comprises four booms witha rotor attached at the two ends of each boom. Two booms may be arrangedon top of and perpendicular to another two booms. A body of the aircraftmay be positioned in the center of all four booms. Flotation devices maybe attached underneath the booms. Boom extensions may extend the boomspast the rotors. A net or multiple nets may be secured to ends of theboom extensions, covering the rotors. The aircraft may be designed tohave a small form factor such that it can be easily transported when itis not flown. The aircraft may be designed for flight over water. Theaircraft may be designed to crash safely without harming a pilot of theaircraft.

FIG. 1 is a diagram illustrating an embodiment of a multicopter withflotation landing gear. In the example shown, boom 108 and boom 114 arein parallel. Booms 116 and 120 are in parallel. Booms 108 and 114 areperpendicular to booms 116 and 120. In some embodiments, a fuselage ofthe aircraft is enclosed by two parallel booms and two perpendicularbooms. In the example shown, fuselage 112 is attached to booms 108, 114,116, and 120. In some embodiments, multiple rotors surround a fuselageof the aircraft. Rotors 106 and 126 are attached to either end of boom108. Rotors 110 and 124 are attached to either end of boom 114. Rotors118 and 104 are attached to either end of boom 116. Rotors 122 and 130are attached to either end of boom 120. Flotation device 128 is attachedunderneath boom 116. Flotation device 132 is attached underneath boom120. In some embodiments, the aircraft comprises two flotation deviceswherein the span between the two flotation devices depends on thedistance between the two parallel booms the flotation devices areattached to. In some embodiments, boom 108, 114, 116, and 120 arearranged such that fuselage 112 is a square or rectangular shaped spacein the middle of the booms. The fuselage may comprise metal tubing usedto build a frame to support and stabilize a seat, steering bar,batteries, and any other appropriate components.

In some embodiments, fuselage 112 comprises a seat and a steeringmechanism. The seat and steering mechanism may be designed for a humanpilot. The fuselage may be uncovered. The absence of a covered orenclosed fuselage may be due to weight constraints. An open fuselage mayallow a pilot greater visibility while flying over water. For example,mist and splashes from a water may hinder visibility to a greater degreein an enclosed fuselage. The fuselage may comprise a flight computer.The flight computer may implement autopilot safety features. Forexample, the flight computer may prevent the aircraft from tilting pasta threshold angle, such as twenty degrees, in order to limit crashes.The flight computer may use sensors to prevent the aircraft fromcolliding with obstacles. The flight computer may be an off the shelfmodel such as a Pixhawk product.

In some embodiments, the multicopter aircraft has a length of 100 inchesor less. The multicopter aircraft may qualify as an ultralight aircraftunder federal aviation regulation guidelines. The multicopter aircraftmay fit in a standard trailer designed to be towed by an automobile. Insome embodiments, the aircraft is designed to be flown over water and assuch does not have attached wheels. A small form factor may allow theaircraft to be easily towed over land. The multicopter may be designedto fit sideways in the trailer such that the width of the aircraft isrelatively unconstrained in comparison to its length. For example, thefour rotors on either side of the aircraft (e.g. rotors 106, 110, 126,and 124) may be larger than the other four rotors of the aircraft. Theaircraft may be wider than it is long in order to have an increasedwingspan and increased flight efficiency.

FIG. 2 is a block diagram illustrating an embodiment of booms and rotorsof a multicopter with flotation landing gear. In some embodiments, theaircraft comprises two parallel booms and two booms perpendicular to thetwo parallel booms, wherein the two parallel booms are attached to thetwo perpendicular booms. In the example shown, boom 200 and boom 204 arein parallel. Booms 206 and 210 are perpendicular to booms 200 and 204.In various embodiments, perpendicular booms are attached usingadhesives, screws, welding, reinforced joints, interlocking parts, orany other appropriate method. In the example shown, a rotor is attachedat both ends of each boom. In some embodiments, the rotors are attachedto an underside of the booms. The booms used may be hollow. The boomsmay be made of a lightweight, strong material. The boom may have adiameter of 2 inches or length of 88 inches. The booms may be waterresistant. In the example shown, rotors 222 and 216 are attached to eachend of boom 200. Rotors 202 and 214 are attached to each end of boom204. Rotors 220 and 208 are attached to each end of boom 206. Rotors 218and 212 are attached to each end of boom 210. In some embodiments,motors used are an off the shelf variety such as A200-8 Hacker Brushlessmotors.

FIG. 3 is a diagram illustrating an embodiment of booms and rotors of amulticopter with flotation landing gear. In the example shown, boomextensions have been deployed to all boom ends. In the example shown,the boom extensions extend past the rotors. In some embodiments, alength of the boom extensions is based upon a rotor swept area. Forexample, a boom extension may be designed to extend the boom apredetermined amount past the furthest reach of a rotor attached to theboom. The boom extension length may be equal to the sum of the radius ofthe rotor's swept area and an additional safeguard distance. In someembodiments, the plurality of boom extensions are attached during flightand the plurality of boom extensions are removed when the aircraft is onland. In some embodiments, the boom extensions are telescoped in or outof the booms. The boom extensions may be extracted or retracted. Theboom extensions may be removed or retracted to decrease the width and/orlength of the aircraft, allowing it to be transported easily andcompactly. In some embodiments, a rotor must be turned to beperpendicular to a boom it is attached to in order to transport theaircraft when the extensions are removed. Turning the rotor may preventthe rotor blade from becoming damaged or allow the aircraft to betransported in a smaller carrier than otherwise.

In the example shown, booms 306 and 310 are in parallel. Booms 300 and304 are perpendicular to and attached to booms 306 and 310. Boom 304originally extended at rotors 302 and 314 or at a short predetermineddistance past the rotors (e.g. a few centimeters to a few inches). Boomextensions applied to boom 304 allow the boom to extend past the sweptarea of rotors 302 and 314. The swept area of a rotor may comprise thecircular area that the rotor travels through when running. The boom mayoriginally be a hollow tube and be open at both ends. The boomextensions may be hollow, open at one end, and closed at the other. Theboom extension may be a tube of a greater or lesser diameter than theboom such that the open end of the boom extension and an end of the boommay be attached by sliding one tube into the other. A boom extension mayplug into a boom up to a stopper or stopping point. A net or protectivematerial may provide tension that holds the boom extensions in. The boomextensions may be always attached to the booms and be folded up when notin use. The boom extensions may be attached to the boom via screws,adhesives, interlocking parts, or any other appropriate method. Theextensions may be installed before flight of the aircraft for safetyreasons.

FIG. 4 is a block diagram illustrating an embodiment of booms, rotors,and protective material of a multicopter with flotation landing gear. Inthe example shown, booms 400 and 402 are in parallel. Booms 404 and 406are in parallel and are perpendicular to booms 400 and 402. The boomshave rotors and boom extensions attached at each end. Protectivematerial 408 is attached. In some embodiments, protective material 408is attached on top of the booms. In various embodiments, protectivematerial 408 comprises netting, a tarp, a cloth, or any appropriatematerial. Protective material 408 may prevent an entity positioned abovethe rotors from being injured by blades of the rotors. Protectivematerial 408 may be flexible, durable, or lightweight. In someembodiments, protective material 408 is able to be rolled or folded.Protective material 408 has an opening near the center of the aircraft,where a fuselage may be positioned. The material may be configured suchthat the fuselage of the aircraft is not covered. The material may beattached to the booms near the fuselage and to each boom extension. Thematerial may be attached via fasteners or any appropriate method thatallows the material to be easily attached or removed. In someembodiments, the material extends over swept areas associated with themultiple rotors. The material may protect a pilot of the aircraft frombeing harmed by a rotor in the event of an accident. The material mayprevent a pilot from being cut by a blade of a rotor in the event thepilot falls off a seat of the aircraft, especially in the event thefuselage is uncovered. In some embodiments, in the event the pilot fallsoff the aircraft, the aircraft senses the pilot is no longer seated andturns off power to the rotors or automatically lands the aircraft. Aseatbelt may be attached to a pin in the aircraft such that in the eventthe pilot is thrown, the seatbelt detaches from the aircraft and pullsout the pin, signaling that an accident has occurred. The protectivematerial may be removed when the aircraft is not being flown. Booms 400,402, 404, and 406 may have fasteners at their ends such that material408 is rolled up and attached to the booms in the event the boomextensions are removed.

FIG. 5 is a diagram illustrating a top view of an embodiment of amulticopter with flotation landing gear. In the example shown, booms514, 522, 528, and 520 surround a fuselage of the aircraft. The fuselagecomprises steering mechanism 516, structure 526, and tank 518. In someembodiments, steering mechanism 516 is rigid and is able to support apilot's expected body weight (e.g. up to 250 pounds). In someembodiments, steering mechanism 516 comprises finger controls for thepilot. Structure 526 may be part of the frame on which a seat isfastened. In some embodiments, the seat of the aircraft is designed tobe straddled. Tank 518 may contain fuel for the aircraft. Tank 518 maybe designed for a pilot to secure her legs on either side, providingstability to the pilot. The fuselage may be attached to the booms via aframe made of metal tubes.

Flotation devices 506 and 524 may be attached underneath booms 520 and522 respectively. In the example shown, rotors are represented by theirswept areas. Rotors 500, 502, 504, 506, 508, 510, 512, and 5230 surroundthe fuselage. Using eight rotors to fly the aircraft may provide anelement of redundancy. The power capability of each rotor may provide anelement of redundancy wherein the rotors possess more power than is morethan is required to fly the aircraft. The rotors may have a 1.3 to 1.6thrust to weight ratio. The thrust to weight ratio may be designed toprovide an element of redundancy. In some embodiments, in the event arotor of the multiple rotors ceases to function the remaining rotors ofthe multiple rotors are sufficient to fly the aircraft in a levelposition. A rotor opposite a malfunctioning rotor may not be used inorder to maintain balance in the aircraft. Motors used to rotate therotors may have a maximum power of 10,000 to 15,000 watts, a diameter of100 to 200 millimeters, or a weight of 2000 to 3000 grams. A rotor blademay have a length of 12 inches to 24 inches.

In some embodiments, the multiple rotors are angled to enhance torque indirectional flight. The rotors may be angled to attain greater yawauthority or increased torque. For example, in the event the rotors arelevel, the aircraft pitches forward to create force as it flies forward.In the event the rotors are tilted forward, the aircraft does not needto pitch forward as far to achieve the same speed. Tilting the rotorsmay decrease a drag experienced by the aircraft. In some embodiments,some of the rotors are pitched forward whereas other rotors are pitchedback. The rotors may be tilted at differing angles in order toefficiently move the aircraft in all directions. In the example shownrotors 500, 502, 512, and 506 may be tilted down such that the left sideof the swept areas of the rotors as shown are at a lower altitude thanthe right side. Rotors 530, 504, 508, and 510 may be tilted or angledup.

In some embodiments, pairs of rotors of the multiple rotors rotate inopposite directions from each other to minimize torque. Each rotorproduces a thrust and a torque about its center of rotation. With anequal number of rotors rotating in each direction, the aircraft'sacceleration about the yaw axis may be canceled out. Rotating pairs ofmotors in opposite direction may allow an aircraft to hover withoutspinning. In the example shown, rotors 504, 508, 512, and 500 may rotateto the left whereas rotors 502, 506, 510, and 530 rotate to the right.

FIG. 6 is a diagram illustrating a side view of an embodiment of amulticopter with flotation landing gear. In some embodiments, themulticopter aircraft is optimized to fly over water and comprisesflotation devices. In the example shown boom 604 and boom 606 areattached perpendicularly to boom 602. In the example shown, flotationdevice 600 is attached to boom 602 via 608 and 610. In some embodiments,608 and 610 are the same dimensions or are made of the same material asthe booms. Structures 608 and 610 may comprise a metal cylinder, a tube,a pipe, or any appropriate connecting structure. In some embodiments,the flotation devices that are attached underneath junctures of booms ofthe aircraft. For example, structures 608 and 610 are directlyunderneath where boom 602 is attached to boom 604 and boom 606respectively. In some embodiments, the positioning of the flotationdevice allows the fuselage to be stably supported. The joints orjunctures may be reinforced.

In some embodiments, the flotation devices are filled with air. Thejuncture of structures 608 and 610 with flotation device 600 may bereinforced to ensure no air escapes from flotation device 600. Theflotation devices may be made of a material that is lightweight,waterproof, and resistant to tears and punctures. The flotation devicesmay be sewn or constructed such that it maintains a desired shapedespite being filled with air. The flotation devices may be concave. Inthe example shown, flotation device 600 has ends that curve up and awayfrom the water. In some embodiments, the flotation devices are curved tominimize interference with the multiple rotors' wash. For example, arotor may be attached under the left end of boom 602. The curvature offlotation device 608 near structure 608 may decrease the extent to whichflotation device 600 blocks air pushed by the rotor.

FIG. 7 is a diagram illustrating a side view of an embodiment of amulticopter with flotation landing gear. In the example shown, thefuselage comprises steering mechanism 706 and tank 708. In the exampleshown, the tank and handlebars are attached to a fuselage frame. Theframe may comprise metal tubing. In some embodiments, the fuselage isattached to a triangulated frame that prevents or reduces twisting. Theframe may be designed to increase stiffness of the aircraft. In theexample shown, frame 712 protrudes over rotors 70 and 702 in atriangular configuration. Steering mechanism 706 and tank 708 areattached to a same sloped side of the frame. In the example shown, frame712 extends below rotors 700 and 702 in a triangular formation. Theframe may provide space for storage, for example of the flight computeror batteries. In the example shown, batteries 710 are attached to frame712. In some embodiments, components of the aircraft are waterproof orwater resistant. For example, batteries 710 may be sprayed with asealing coat or stored in an airtight box. Flotation device 704 isattached underneath rotors 700 and 702.

FIG. 8 is a diagram illustrating a front view of an embodiment of amulticopter with flotation landing gear. In the example shown, rotors800 and 816 are attached underneath boom 802. Booms 814 and 818 areperpendicular to boom 802. Flotation devices 804 and 812 are attached oneither side of the aircraft. In the example shown, tank 810 and steeringmechanism 808 are attached to frame 806. Steering mechanism 808 maycomprise handlebars. In the example shown, two beams extend from themiddle of steering mechanism 808. The two beams are then furtherattached to main supporting booms of the aircraft. In some embodiments,the fuselage frame is designed to be stiffened or resist contortion thatoccurs due to natural frequencies. Stiffening the frame may causenatural frequencies of the aircraft to be higher and easier to avoid.

Although the foregoing embodiments have been described in some detailfor purposes of clarity of understanding, the invention is not limitedto the details provided. There are many alternative ways of implementingthe invention. The disclosed embodiments are illustrative and notrestrictive.

What is claimed is:
 1. A multicopter aircraft, comprising: multiple rotors, each mounted substantially horizontally on a distal end of a boom; and a plurality of removable boom extensions, each boom extension being associated with a corresponding boom and each boom extension being configured to extend an associated distal end of said corresponding boom by an amount determined based at least in part on a swept area associated with a rotor mounted at or near said associated distal end, wherein the boom extensions are adapted to receive a material extended over the booms to provide a barrier between an occupant of said aircraft and the multiple rotors.
 2. The aircraft of claim 1, further comprising the material, wherein the material extends over a far end of at least one of the boom extensions to separate the occupant from the multiple rotors.
 3. The aircraft of claim 1, wherein the material extends over swept areas associated with the multiple rotors.
 4. The aircraft of claim 1, wherein the aircraft has a length of 100 inches or less.
 5. The aircraft of claim 1, wherein the multiple rotors surround a fuselage of the aircraft.
 6. The aircraft of claim 1, wherein a fuselage of the aircraft comprises a seat and a steering mechanism.
 7. The aircraft of claim 1, further comprising a flight computer configured to prevent the aircraft from tilting past a threshold angle.
 8. The aircraft of claim 1, further comprising two parallel booms and two booms perpendicular to the two parallel booms, wherein the two parallel booms are attached to the two perpendicular booms.
 9. The aircraft of claim 1, further comprising two parallel booms and two booms perpendicular to the two parallel booms, wherein a fuselage is enclosed by the two parallel booms and the two perpendicular booms.
 10. The aircraft of claim 1, wherein in the event a rotor of the multiple rotors ceases to function, the remaining rotors of the multiple rotors are sufficient to fly the aircraft in a level position.
 11. The aircraft of claim 1, wherein pairs of rotors of the multiple rotors rotate in opposite directions from each other to minimize torque.
 12. The aircraft of claim 1, wherein the multiple rotors are angled to enhance torque in directional flight.
 13. The aircraft of claim 1, further comprising a fuselage with a triangulated frame that prevents or reduces twisting.
 14. The aircraft of claim 1, wherein a fuselage of the aircraft is unenclosed.
 15. The aircraft of claim 1, wherein the aircraft is optimized to fly over water.
 16. The aircraft of claim 1, wherein the aircraft comprises flotation devices.
 17. The aircraft of claim 1, wherein the aircraft comprises flotation devices that are attached underneath junctures of booms of the aircraft.
 18. The aircraft of claim 1, further comprising flotation devices filled with air.
 19. The aircraft of claim 1, further comprising flotation devices having curved ends.
 20. The aircraft of claim 1, further comprising flotation devices that are curved to minimize interference with the multiple rotors' wash. 